Fiddler rocks. Fiddler is a free web debugging proxy for any browser, system or platform. I’ve only ever used it on Windows so I can’t speak to how it performs on any other OS, but on Windows it’s pretty great.

To go into a little more detail, Fiddler captures every request your browser makes and lets you save, retrieve, and analyze them. Mostly I use it for simple things like seeing the full error message and headers returned by a failed api call when all my javascript is telling me is that “something went wrong.” Thanks js, you’re a big help.

A lot of why I like Fiddler so much is just personal preference. The network tab in Chrome dev tools does a lot of the things I use Fiddler for, but I like Fiddler’s interface better. Fiddler does have some differences, though. If you want to save a few rounds of requests across page refreshes so you can compare them to each other, Fiddler lets you do that. It also has a more powerful filtering system than Chrome dev tools, so you only have to see the requests you care about.

As much as I love Fiddler, there is one caveat I need to mention. Firefox is totally incapable of coping with Fiddler unless you change some settings. I strongly recommend that you do that immediately if you install Fiddler because you will forget that you have Fiddler running, try to test something in Firefox, and freak out because everything is suddenly broken (not that I’ve ever done that. Repeatedly). It’s not, Firefox should just be ashamed of itself. Even IE can handle a freaking proxy. You used to be cool, FF. Now you’re like a broken down racecar that’s getting lapped by a go-kart. With square wheels. That’s been set on fire.

Why should you care about Fiddler? It might be better than what you’re doing right now. Having better tools to do the tedious stuff for you means more time for actual development, even if you have to invest a few minutes up front to figure out if Fiddler is actually better than what you’re using right now. It won’t magically make you a better developer, but it will give you more time for development, which can be pretty close to the same thing :)